Electrically released latching switch for timer-controlled appliances and the like

ABSTRACT

Switch means, movable between an &#39;&#39;&#39;&#39;OFF&#39;&#39;&#39;&#39; and an &#39;&#39;&#39;&#39;ON&#39;&#39;&#39;&#39; position. Latch means are provided in association with the switch means for holding the switch means in its &#39;&#39;&#39;&#39;ON&#39;&#39;&#39;&#39; position. The latch means is responsive to an electrical signal from an external source to release the switch means for return to its &#39;&#39;&#39;&#39;OFF&#39;&#39;&#39;&#39; position.

1 United States Patent Zane [ 541 ELECTRICALLY RELEASED LATCHING SWITCH FOR TIMER- CONTROLLED APPLIANCES AND THE 1 June 27, 1972 3,211,846 10/1965 Hutt et a1. ..200/5 E 2,952,757 9/1960 Ellenberger ..337/77 2,197,726 4/1940 Johnson v.337/77 3,346,706 10/1967 Woodward ZOO/S F.

Primary Examiner-Harold Broome Attorney-Melville, Strasser, Foster & Hoffman 57 ABSTRACT Switch means, movable between an OFF" and an "ON" position. Latch means are provided in association with the switch means for holding the switch means in its ON position. The latch means is responsive to an electrical signal from an external source to release the switch means for return to its OFF position.

6 Claims, 6 Drawing figures i 20b (20C 200' 6 25a 2 1, I 23 5 N 3 :2 25b PA'TENItIIIuIIzv sIz 3.$73,53l SHEET 1 OF 2 I ELECTRONIC DIGITAL COUNTER-TYPE TI 31 I CYCLE SELECT. OUTYPUT 'DEVICESI -1 oswncn UNIT IuON OFF I 7 9 lo SWII'cI-I I I I APPI. ANCE DEVICES I i I MAIN POWER SouRc'E :FIGI 5 200. 1 b 20c 20a 20a ZOF 203 20h x I I T I I Z2 I I6 l9 l5 l9 vL9 l9 I5 II ZI I TAXES. (Mi [t 7 I? I7 I 26 5 26b I I 25/ V I :1 Lu 33 l I I5 24( l I I l I I To DISH WASHER v CIRCUI' 'IY G WER VTERMINAL I LINE I v SIGNAL INPU TERMINAL. 33b

I ATTORNEYS 5 W VICTOR H. ZANE 9510 v ,BY )y I y ELECTRICALLY RELEASED LATCKING SWITCH FOR TIMER-CONTROLLED APPLIANCES AND THE LIKE BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to switch means, as for example in the circuitry of timer-actuated devices, and more particularly to switch means having latching means in association therewith, which is responsive to an electrical signal from the timer or the like.

2. Description of the Prior Art The switch means of the present invention may be used in many applications. While not intended to be limiting, for purposes of an exemplary showing the switch means will be described with respect to its application in an automatic dishwashing machine. A dishwashing machine is typical of the general class of appliances or the like to which the switch means of the present invention may be advantageously applied.

In present day dishwashing machines, various operations are controlled or initiated by electrical means. A dishwashing machine generally comprises a vat having a front or top opening with a suitable closure means. There is ordinarily an electric motor which drives one or more pumps, and which often drives an impeller for showering the tableware in the vat with water. In many such machines a pump is employed of such character as to result in the circulating of the water when the motor is driven in one direction, and the draining in the vat when the motor is driven in the opposite direction. The dishwasher generally contains additional electrically operated elements, which may be varied as to number and kind, but which may include (without limitation) such elements as a safety door switch, a heater, solenoid operated valves, a general illuminant, indicator means and solenoid operated means for injecting surface-active or other substances into the vat. The na ture and function of these various means are well known in the art and do not constitute a limitation on the present invention. Thus, for convenience, these various elements will hereinafter be referred to as appliance devices.

Automatic dishwashers are arranged to carry on a plurality of operations, through the agency of the various devices, in sequence. This sequential series of operations is generally referred to as a cycle. For example, a typical automatic dishwasher is arranged to carry on in sequence a cycle of operations which may be designated as first rinse, drain, first wash, drain, second rinse, drain, second wash, drain, third rinse, drain, fourth rinse, drain, dry and drain. Other cycles of which the machine is capable are generally made up of selected ones of the above listed operations.

The carrying on of these cycles is generally controlled by a timer, of which various varieties are known. For example, timers have been used comprising a motor driven device like a commutator which results in sequential, and in some instances simultaneous, opening and closing of electric switches. In similar fashion, timing devices have been used, comprising a motor driven rotating element providing a plurality of cammin g surfaces for operating electrical switches.

More recently, workers in the art have turned their attention to electronic digital counting-type timers. Such timers display a versatility hitherto unobtainable. They are not subject to wear and adjustment problems, as are mechanical timers. In addition, they provide all of the advantages characteristic of electronic devices.

Finally, the dishwashing machine is usually provided with a series of pushbuttons or the like, by which a desired cycle may be selected by the operator. The switch circuits, as determined by a specific button selection, work in conjunction with the timer to control the various dishwashing machine devices. In usual practice, the cycle selector pushbuttons comprise a part of a switch unit so constructed that only one button may be depressed at any given time. Examples of switch units suitable for this purpose are taught in United States Letters Patent Nos. 2,819,356 and 2,431,904.

With some types of circuitry, as for example, those involving the use of an electronic digital timer, the ending of the desired sequence of functions is most conveniently achieved by the initiation of 'an electrical signal. Accomplishing the function of maintaining circuit power between ON" and OI-"F" signals normally involves the use of electro-mechanical relays. Such relays are, however, costly. In addition, a momentary switch action is normally required to cause the closing of the relay contacts.

While its use is not so limited, the electrically released latching switch of the present invention will be described, for purposes of an exemplary showing, in its application as an ON-OFF" switch for a dishwashing machine. The switch is mechanically latched in its ON position during the operation of a machine cycle, and is released to its "OFF" position by an electrical signal from the timer at the end of the cycle. The electrically released latching switch of the present invention is easy and inexpensive to manufacture and positive in its action.

BRIEF SUMMARY OF THE INVENTION The invention is directed to an electrically released latching switch for use in the circuitry of a timer actuated appliance or the like. The switch means comprises an ON-OFF" switch controlling the electrical power to the appliance. The switch comprises a switch member movable between an OFF position and an ON position. Latch means are provided for mechanically holding the switch means in its ON position for the duration of time the appliance is to be actuated. At the end of the desired time interval, the timer sends an electrical signal to the latch means, causing the latch means to release the switch member to its OFF position.

In one embodiment of the present invention, the latch means may comprise a bi-metallic element surrounded by a heating element. When the heating element is actuated by an electrical signal from the timer, the bi-metallic latch means will change its configuration, releasing the switch means to its OFF" position.

BRIEF DESCRIPTION OF TI-IE DRAWINGS FIG. 1 is a simple, diagrammatic illustration showing the basic elements of an automatic dishwasher circuit.

FIG. 2 is a side elevational view, partly in cross section, of a cycle selector switch unit suitable for use with the present invention.

FIG. 3 is a bottom view of the switch unit of FIG. 2, with a part broken away, and illustrating the application of the electrically released latching switch of the present invention thereto.

FIG. 4 is a fragmentary perspective view of the structure of FIG. 3.

FIG. 5 is a fragmentary elevational view of the structure of FIGS. 3 and 4.

FIG. 6 is a simple diagrammatic illustration showing the electrical circuitry of the embodiment of FIGS. 3-5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 diagrammatically illustrates the major elements in a circuit for an automatic dishwasher. The diagram of FIG. 1 does not constitute an electrical circuit diagram, per se, but rather is simply a representation of the component parts.

A main power source is indicated at 1. The main power source may simply comprise a source of ordinary household current. An ON-OFF" switch is shown at 2 and is the means by which the operation of the dishwasher is initiated and terminated.

Element 3 comprises a cycle selector switch unit. The switch unit may be of the pushbutton type and enables the dishwasher operator to select any desired one of the cycles the dishwashing machine is capable of performing. The sequence of operations, making up a particular cycle, is controlled by an electronic digital counter-type timer indicated at 4.

The rectangle 5 diagrammatically indicates the presence of output devices. The purpose of the output devices is to serve as an interface between the low-power digital timer 4 and the high-power devices 6 through 10 of the dishwashing machine. For example, a typical control output from the timer device may be 1 milliamp at l0 volts, while a typical appliance device controlled thereby might comprise a motor drawing 10 amps at 100 volts. The output devices 5 may be of any suitable type well known in the art, and do not constitute a limitation on the present invention.

While five appliance devices are diagrarrunatically indicated at 6 through 10, their number and nature does not constitute a limitation on the present invention. As indicated above, these devices may include one or more solenoid operated valves, an electric heater, electrically operated devices for delivering measured increments of detergent or the like, one or more pump motors, a series of indicator lights, and the like.

FIG. 2 illustrates an exemplary form of cycle selector switch unit. The switch unit shown is of the multiple pushbutton type taught in the above mentioned Us. Letters Patent Nos. 2,431,904 and 2,819,356.

The switch unit comprises a base or body 1 1 having an insulative bottom cover member 12. The body is provided at its ends with extensions 13 and 14. Extensions l3 and 14 have perforations l5 and 16 therethrough, by which the switch unit may be mounted to desired surface with bolts, screws or other fastening means.

The body 1 1 is hollow and has on its top surface a plurality of upwardly extending hollow portions 17. The portions 17 have openings 18 in their top surfaces through which the plungers 19 of pushbuttons 20a through 20h extend. Each of the pushbutton plungers 19 may carry a hairpin-shaped detent spring 21. The springs 21 cooperate with projections 22 on opposite sides of openings 18 to maintain their respective pushbutton-plunger assemblies in proper position. The plunger of each pushbutton terminates in a rounded operating surface 23, the purpose of which will be described hereinafter.

The chamber 24, formed within the hollow body 11, is adapted to receive a plurality of longitudinally extending slide elements in side-by-side relationship. For purposes of an exemplary showing, seven such slides are shown at through 31 in FIG. 3. For purposes of clarity, only two slides (25 and 26) are shown in FIG. 2.

The upper edge of each slide is configured to have a plurality of cam surfaces adapted to cooperate with the operating surfaces 23 of the pushbutton plungers 19. As is explained in the above mentioned United States Letters Patent No. 2,819,356, the various cam surfaces on the upper edges of the slides are so arranged that when a given one of the pushbuttons 20a through 20h is depressed, selected ones of the slides will be caused to move longitudinally. Just how this is accom plished can be readily determined from FIG. 2. If, for example, pushbutton 20a is depressed, it will be noted that slide 26 will move to the left by virtue of the interaction of plunger operating surface 23 and the slide cam surface 26a. It will further be noted, however, that slide 25 will remain in the position shown since no cam surface is presented thereon which will be acted upon by plunger operating surface 23. If pushbutton 20b is depressed, slide 26 will again move to the left by the interaction of its cam surface 26a. The surface 25a of slide 25 will not cause movement of slide 25. The opposite is true, on the other hand, if pushbutton 200 were depressed. I-Iere, cam surface 25b would interact with the operating surface 23 of pushbutton 20c to move slide 25 to the left. Meanwhile, surface 260 on slide 26 will not cause longitudinal movement of slide 26.

As can be clearly seen from FIGS. 2 and 3, the switch unit is provided with a longitudinally extending row of terminals 32 along one edge thereof. The terminals 32 extend downwardly through perforations in the insulative cover 12. Along the opposite edge of the switch unit there is a second series of downwardly extending terminals 33. The terminals 33 extend through notches in the insulative cover 12. In association with each of the terminals 32 there may be a movable contact arm 34 extending transversely of chamber 24. The movable contact arm 34 is connected to, or may comprise an integral part of, its respective terminal 32. Each of the terminals 33 may have a contact portion (not shown) adapted to cooperate with one of the movable contact arms 34. Contact arms 34 are generally made of resilient metallic material and are biased to a position where they make contact with their respective ones of the contact portions of terminals 33. In FIG. 2, the movable contact arms 34 are illustrated in their normal positions wherein they would be contacting their respective contact portions of terminals 33.

It will be understood by one skilled in the art that it is not required that a switch contact arm be provided for each terminal 32, nor a contact portion for each terminal 33. In some cases, a number of terminals may be ganged together for purposes of multiple connection.

From FIG. 2, it may be seen that the individual slides have their bottom edges configured to form cam surfaces. These bottom cam surfaces are separated by downwardly extending projections 35 terminating in bearing surfaces for the individual slides which cooperate with the upper surface of the insulative cover 12.

It will be evident that longitudinal movement of selected ones of the slides, caused by the depression of a desired one of pushbuttons 20a through 20h will, cause selected ones of the movable contact arms 34 to make or break contact with their respective contact portions of terminals 33. Thus, in FIG. 2, if slide 25 were to move to the left, the lower cam surfaces 250 and 25d would cause the adjacent ones of the movable contact arms 34 to break contact with their respective contact portions of tenninals 33.

From the above description it will be understood that the depression of anyone of the pushbuttons 20a through 20h will cause movement of selected ones of the slides 25 through 31. This, in turn, will cause the making and breaking of contact between selected ones of the movable contact arms 34 and their respective contact portions of terminals 33. The upper cam surfaces on the slides are usually so arranged that when any desired one of the pushbuttons 20a through 20h is depressed, any other one of the pushbuttons which is already depressed will be returned to its non-depressed position. Thus, only one pushbutton can remain depressed at a given time.

It is common to make up such switch units with a view toward the particular application for which they are to be used. Thus, a switch unit of the type shown in FIGS. 2 and 3 may by made up with only that number of terminals 32 and 33 and switch arms 34 needed to perform the switching functions required of the unit.

Finally, it is not uncommon to obtain certain other actions from such switch units. For example, one or more of the slides may be spring loaded so as to have a momentary action. This may be accomplished by the structure shown in FIG. 3. A rivet, boss or the like 36 may be provided in switch body 1 1. A spring 37 is mounted thereon, having one arm 37a bearing against an inside surface of the switch body. The other arm 37b of spring 37 is adapted to contact one of the downwardly depending extensions 35 appropriately located on the slide to be spring loaded. In FIG. 3, slide 28 is shown as having an extension 35 so positioned.

FIGS. 3, 4 and 5 illustrate how the principle of the present invention may be used to incorporate the ON-OFF" switch 2 of FIG. 1 into the cycle selector switch unit 3 of FIG. 1, it being understood that the cycle selector switch unit 3 is of the type shown in FIG. 2.

In order to accomplish this, the cycle selector switch unit will have to be connected in the main power line of the dishwasher. For purposes of an exemplary showing, it can be assumed that the main power line is connected to that one of switch tenninals 33 designated as 33a and hereinafter referred to as the power input terminal. That one of switch terminals 32, designated as 32a, is connected to the dishwasher circuitry. It will be understood that the switch tenninal 32a will have a movable contact arm 34 adapted to cooperate with the contact portion of power input temiinal 33a. When contact is made, power will be supplied to the dishwasher circuitry. When contact is broken, no power will be supplied to the dishwasher circuitry.

In order to make and break the above contact, it will be understood that an appropriate slide must be provided in the switch unit. For purposes of an exemplary showing, it will be assumed that the spring loaded slide 28 controls that switch arm making and breaking contact between terminals 32a and 33a. When the slide 28 is held in its left-hand-most longitudinal position (as seen in FIG. 3) by spring 37, it is to be assumed that contact between terminals 32a and 33a is broken. The slide 28 may have an upper edge so configured as to provide cam surfaces such that the slide will be moved to its righthand-most longitudinal position (as seen in FIG. 3), against the action of spring 37 whenever any one of the cycle selector pushbuttons a through 20h is depressed. Under these circumstances, when the dishwasher operator depresses any desired one of cycle selector pushbuttons 20a through 20h, he will not only make his cycle selection, but also will start the operation of the dishwashing machine. This is true because slide 28 will assume its right-hand-most position (as seen in FIG. 3) and the contact will be made between the terminals 32a and 33a.

In order for power to be supplied to the dishwasher circuitry throughout the selected cycle, it is necessary that means be provided to maintain slide 28 in its right-hand-most position (as seen in FIG. 3). The means for accomplishing this are shown in FIGS. 3 through 5.

First of all, slide 28 is provided with a downwardly depending extension 28a of such length that it will extend through a slot 38 formed in the insulative bottom cover 12. When slide 28 is in its normal power-ofi position, the extension 28a will be in the position shown in FIGS. 3 and 4. When the slide 28 is in its power-on position, the extension 28 will assume the position shown in FIG. 5.

The slide 28 is held in its power-on position by the interaction of extension 28a and a hook-shaped latch means 39, as shown in FIG. 5. The latch means 39 is a bi-metallic element, having a bent over end 39a which mechanically engages slide extension 280. A heating element is provided in close proximity to the bi-metallic latch means. For purposes of an exemplary showing, the heating element is illustrated (at 40) in the form of a resistance wire wrapped about the latch means 39. A portion of the bi-metallic latch means 39 has an electrical insulator 40a wrapped thereabout. One end of the resistance wire 40 is connected directly to the bi-metallic latch means 39 by adhesive or the like, as at 39b. A few turns of the resistance wire are in direct contactwith the bi-metallic latch means, the remainder of the resistance wire being wrapped about the insulator 40a. The other end of the resistance wire 40 is connected to a metal band or clamp 40b, crimped about insulator 40a.

An exemplary mounting for the latch means is generally indicated at 41. The mounting comprises a first metallic plate 42, a block of insulative material 43, a second metallic plate 44 and a second layer of insulative material 45. This entire assembly is held together by insulated rivet-like means 46 or the like. The latch means lies between elements 43 and 44.

The metallic plate 42 has a lateral extension 42a affixed to that one of the switch unit terminals 33 designated as 33b. In similar fashion, the second metallic plate 44 has a lateral extension 44a affixed to switch unit terminal 320.

As a consequence, the plates 42 and 44 and their lateral extension 42a and 44a serve not only to mount the latch means to the switch unit, but also as conductors for the heating element or resistance wire 40. This is true because the bi-metallic latch means 39 and plate 44 are in direct contact with each other. Thus, one end of resistance wire 40 is connected to terminal 32a via the bi-metallic latch means 39 and plate 44. The band 40b has an electrical connection to plate 42 (not shown). In this fashion, the other end of the resistance wire 40 is connected to temiinal 33b. Switch unit terminal 33b is connected through output devices 5 to the counter-type timer 4, whereby a stop signal from the timer can actuate the heating element or resistance wire 40. This circuitry is illustrated in FIG. 6.

It will be understood that the bi-metallic latch means 39 is biased by its configuration toward the position in which it is shown in FIG. 5. When the heating element or resistance wire 40 is actuated by a signal from the timer, the bi-metallic ele ment will bend downwardly (as seen in FIG. 5) to a position where it no longer engages the extension 28a of slide 28. Therefore, slide 28 moves to the left (as seen in FIGS. 3 through 5) to its power-off position under the influence of spring 37. As the bi-metallic latch means 39 cools, it will come to rest on the top surface of the slide extension 28a as shown in FIG. 4. In this position, it will not interfere with movement of slide 28 and its extension 28a to the right. When the slide is moved to the right, the bi-metallic element 39 will snap down into the position shown in FIG. 5.

The operation of the electrically released latching switch of the present invention may be described as follows. The dishwasher operator loads the vat with tableware and closes the vat door. It will be understood that the slide 28 will be in its power-off position, and consequently the slide extension 28a and bi-metallic latch means 39 will be in the positions shown in FIGS. 3 and 4.

When the operator determines what cycle he wishes the machine to perform, he depresses the appropriate one of the cycle selector pushbuttons 20a through 20h. It will be remembered that depression of any one of these pushbuttons will cause the slide 28 to move to the right (as seen in FIG. 3) against the action of spring 37 As a consequence, the slide extension 28a will also move to the right and the bi-metallic latch means 39 will snap into the position shown in FIG. 5. Thus, throughout the operating cycle of the dishwashing machine, the slide 28 will be held in its power-on position by the latch means 39. As a consequence, connection is made between switch unit terminal 32a (connected to the dishwasher circuitry) and terminal 33a (to which the main power line is attached) and power will be supplied to the dishwashing machine devices.

Upon completion of the cycle, the electronic digital counter will initiate a power-oh" or stop signal at terminal 33b. This signal will energize the heating element or resistance wire 40, causing the bi-metallic latch means 39 to bend downwardly and release the slide 28 and its lug. When the slide 28 moves, through the agency of spring 37, to the left (as seen in FIGS. 3 through 5) connection between switch unit terminals 32a and 33a will be broken and power will be discontinued to the dishwashing machine. As it cools, the bi-metallic latch means 39 will assume the position shown in FIG. 4, where it will remain until the next time the operator actuates one of the cycle selector pushbuttons 20a through 20h.

Modifications may be made in the invention without depart ing from the spirit of it. For example, in the above described embodiment the electrical resistance of the bi-metallic latch means itself could be used, where sufficient current is available. This would eliminate the resistance wire 40 and insulator 40a.

A solenoid could be substituted for the bi-metallic latch means 39. Thus, the coil illustrated in FIG. 6 could be the coil of a solenoid. When a solenoid is used, a movable latch lever, spring loaded to the latching position would be required. The solenoid would be so positioned as to trigger the latch lever to its un-latched position.

In the above described embodiment, all of the pushbuttons 20a through 20h are described as being used to select a particular machine cycle. It is within the scope of the invention to connect one of the pushbuttons in such a way that it will serve to cancel a cycle already in progress.

In addition, the principle of the present invention is not limited to switches of the pushbutton variety. Cycle selector switches of a rotary type are common, wherein a single knob is rotated to a desired setting. This knob is shaft-connected to switch actuating cams to established the desired circuitry. A momentary switch action of the nature above described could then be obtained by longitudinal movement of the shaft (push in or pull out). In such a case the shaft would then be similarly latched in the spring-loaded position to maintain circuits until electrically released, by any suitable means such as a bi-metaL lic latch, a solenoid, or the like.

Finally, the present invention is not limited to the location of the electrically released latching switch in association with the cycle selector switch. For example, the ON-OFF" switch of the dishwashing machine could be a wholly separate switch unit. So long as the switch unit had a switch element (movable between a power-on and a power-H position), which was capable of being latched in the power-on position, the same result could be achieved. By the same token, it will be understood by one skilled in the art that the present invention is not limited to an ON-OFF" usage, or use with appliances only.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In an electrical appliance of the type having a timer and being capable of performing a plurality of cycles, each cycle comprising a plurality of events in sequence and having a cycle selector switch comprising a housing, a plurality of stationary contacts and a plurality of movable contacts within said housing, a plurality of slides within said housing movable longitudinally of said housing between first and second positions, each of said slides having a first set of cam surfaces thereon adapted in at least one of said first and second positions of said slide to close at least one of said movable contacts on at least one of said stationary contacts, a plurality of cycle select pushbuttons having plungers extending into said housing, each of said slides having a second set of cam surfaces thereon adapted to cooperate with said pushbutton plungers whereby depression of any one of said cycle select pushbuttons will move selected ones of said slides between their respective first and second positions, the improvement comprising connecting one of said movable contacts and its cooperating stationary contact in the main power line to the appliance so that when said last mentioned contacts are closed electrical power will be supplied to said appliance and when they are open electrical power to said appliance will be interrupted, the first set of cam surfaces on one of said slides being so arranged that when said last mentioned slide is in its first position said power line contacts will be open and when said slide is in its second position said power line contacts will be closed, means for biasing said last mentioned slide to its first position, said second set of cam surfaces on said last mentioned slide being so configured that depression of any one of said cycle select pushbuttons will shift said slide to its second position, latch means for mechanically engaging and maintaining said last mentioned slide in its second position when it has been moved thereto by actuation of one of said cycle select pushbuttons, said latch means being responsive to a signal from said timer to release said last mentioned slide, said slide thereafter being returned by said biasing means to its first position, whereby depression of any one of said cycle select pushbuttons will select the cycle to be performed by the appliance and supply electrical power to the appliance, which electrical power will be interrupted by a signal from the timer at the end of the cycle.

2. The structure claimed in claim 1 wherein said timer is an electronic digital timer.

3. The structure claimed in claim 1 wherein said latch means comprises a bi-metallic element and means are provided whereby said electrical signal from said timer heats said bi-metallic element resulting in mechanical deflection thereof to release said last mentioned slide.

4. The structure claimed in claim 3 wherein said bi-metallic element is mounted exteriorly of said housing and has a hookshaped portion, said last mentioned slide having an extension thereon extending through a slot in said housing, said hookshaped rtion of saidbi-metallic element and said slide extension ing so positioned when said slide is moved to its second position that said hook-shaped portion mechanically engages said slide extension maintaining said slide in its second position, said bi-metallic element being so constructed that when it is heated by said heating means said hook-shaped portion is disengaged from said slide extension by mechanical deflection of said bi-metallic element and said slide is returned to its first position by said biasing means.

5. The structure claimed in claim 4 wherein said heating means comprises a resistance wire wrapped about said bimetallic element.

6. The structure claimed in claim 5 wherein said timer is an electronic digital timer. 

1. In an electrical appliance of the type having a timer and being capable of performing a plurality of cycles, each cycle comprising a plurality of events in sequence and having a cycle selector switch comprising a housing, a plurality of stationary contacts and a plurality of movable contacts within said housing, a plurality of slides within said housing movable longitudinally of said housing between first and second positions, each of said slides having a first set of cam sUrfaces thereon adapted in at least one of said first and second positions of said slide to close at least one of said movable contacts on at least one of said stationary contacts, a plurality of cycle select pushbuttons having plungers extending into said housing, each of said slides having a second set of cam surfaces thereon adapted to cooperate with said pushbutton plungers whereby depression of any one of said cycle select pushbuttons will move selected ones of said slides between their respective first and second positions, the improvement comprising connecting one of said movable contacts and its cooperating stationary contact in the main power line to the appliance so that when said last mentioned contacts are closed electrical power will be supplied to said appliance and when they are open electrical power to said appliance will be interrupted, the first set of cam surfaces on one of said slides being so arranged that when said last mentioned slide is in its first position said power line contacts will be open and when said slide is in its second position said power line contacts will be closed, means for biasing said last mentioned slide to its first position, said second set of cam surfaces on said last mentioned slide being so configured that depression of any one of said cycle select pushbuttons will shift said slide to its second position, latch means for mechanically engaging and maintaining said last mentioned slide in its second position when it has been moved thereto by actuation of one of said cycle select pushbuttons, said latch means being responsive to a signal from said timer to release said last mentioned slide, said slide thereafter being returned by said biasing means to its first position, whereby depression of any one of said cycle select pushbuttons will select the cycle to be performed by the appliance and supply electrical power to the appliance, which electrical power will be interrupted by a signal from the timer at the end of the cycle.
 2. The structure claimed in claim 1 wherein said timer is an electronic digital timer.
 3. The structure claimed in claim 1 wherein said latch means comprises a bi-metallic element and means are provided whereby said electrical signal from said timer heats said bi-metallic element resulting in mechanical deflection thereof to release said last mentioned slide.
 4. The structure claimed in claim 3 wherein said bi-metallic element is mounted exteriorly of said housing and has a hook-shaped portion, said last mentioned slide having an extension thereon extending through a slot in said housing, said hook-shaped portion of said bi-metallic element and said slide extension being so positioned when said slide is moved to its second position that said hook-shaped portion mechanically engages said slide extension maintaining said slide in its second position, said bi-metallic element being so constructed that when it is heated by said heating means said hook-shaped portion is disengaged from said slide extension by mechanical deflection of said bi-metallic element and said slide is returned to its first position by said biasing means.
 5. The structure claimed in claim 4 wherein said heating means comprises a resistance wire wrapped about said bi-metallic element.
 6. The structure claimed in claim 5 wherein said timer is an electronic digital timer. 